Posts Tagged: Garden
The Invasion of the Voles
Take it from me, you really do not want voles (also called meadow mice) moving into your garden. They are larger than a house mouse or deer mouse but do not quite reach the size of an adult gopher or rat. Although it is said that they can mature to 5–8 inches long including the tail, I don't believe that I've seen one any larger than about 5 inches… and I have seen a whole lot of them. With their charming pudgy shape, beady black eyes, small ears, soft gray/brown fur, and rather short and oddly furry tail, their appearance could be thought of as somewhat cute or endearing. That is, until you experience how quickly they can lay waste to your beloved garden.
When they are not ravaging your garden plants, these rodents spend much of their time hiding in their burrows. They are most likely to be seen in the cooler parts of the day such as dawn and dusk, when they dash from one burrow to another, or scurry from dining on your favorite plant into the safety of their burrow. The burrows have openings that are 1 ½ to 2 inches wide. There are often obvious runways from the burrows where soil is trampled down by their repeated scampering back and forth. Voles will happily burrow into both mulch and soil, and where there are dense weeds or long grass growing (a favored habitat), voles will create distinctive tunnels through the vegetation.
Vole populations regularly go through cycles of low to high numbers. Their numbers generally peak each 3 to 6 years or so, but don't count on being able to guess when the next vole invasion will occur. These cycles are not at all predictable. Their numbers can increase to staggering amounts during a population explosion, soaring up to as many as several thousand per acre. I'm not really surprised by this. There are so many in my garden right now that it can be difficult to avoid stepping on one as four or five of them dash across the garden path.
If you have voles in your garden, you already know that they eat a very wide variety of plants. Unlike rats and mice that are out and about wreaking havoc at night, voles are active both day and night, and year-round. Also unlike rats and mice who have favorite foods and tend to go after sweet, ripe fruits and the most succulent vegetables, voles are not terribly picky. In my garden they have killed or severely maimed a wide variety of plants including zucchini, cucumber, green bean, tomato, and artichoke. Basil, dill and parsley are some herb plants that may be there one day and gone the next. They don't just sample tasty fruit or tender young sprouts (although they do enjoy those too), but they gnaw down entire plants. They have decimated my marigold plants, eaten my yarrow to the ground, and chewed off the base of my sunflower and cosmos flower plants—just to watch them tip over and die. The most surprising of all was when they began chewing through the stems and beheading my aeonium succulent plants.
Voles do take an occasional break from their feeding frenzy to breed and have their 5 to 10 litters of offspring each year. Some sources say that they can have 3–6 young at a time, and others say up to 11. One redeeming quality is their short lifespan of just a few months to a year, and the fact that after a season of super high numbers the population tends to go back to normal. During these normal times, I imagine that they stick to their usual habitats of open meadows and fields where they dine on wild plants and grasses, bulbs, tubers, and seeds. Like me, you may see a few, or no voles at all in your garden during these good times.
I have included two links for your reading pleasure. They list the control methods that are the most effective such as habitat modification (make the area less hospitable to them), trapping (setting many, many mouse traps), and exclusion (creating impassable barriers around your garden, your garden beds, or even individual plants). Because of the large numbers of voles that can be present during a population explosion, exclusion is often the most important option. I find that wire hardware cloth makes a good barrier if it is about 12 inches tall. Make sure it surrounds the plants completely, and bury it into ground at least 3 inches deep. Metal roof flashing makes a very effective barrier. It is metal sheeting sold in hardware stores. It comes in rolls with varying widths. Unlike gophers, who dig deep burrows, voles will dig down only a few inches. They are not very athletic and don't climb or jump very well like rats can, so barriers don't have to be terribly tall to be effective.
Voles are an important part of the natural food chain. They are prey for a variety of predators including hawks, crows, owls, snakes, raccoons, bobcats, foxes, coyotes, opossums, and domestic cats. This is the reason why I ask that, although it is listed as one of the methods of control, please do not use poisons to reduce their numbers. Poisoned sick, and dying voles are an easy snack for hungry wildlife and pets, and secondary poisoning poses a great danger to these animals.
This is a very good article about voles, moles, and gophers. It covers their varying habits, how to identify them, and describes in detail the steps to take to reduce the damage they do in our gardens:
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=49119
This UC IPM (integrated pest management) link is an excellent source for information on voles:
https://ipm.ucanr.edu/home-and-landscape/voles/pest-notes/#gsc.tab=0
If you are one of the unfortunate gardeners who is suffering from the invasion of the voles, I feel your pain. But take heart! In my experience, the population will decline to normal numbers in the winter. In the meantime, I wish you the best and hope that your garden will survive mostly intact until the invasion ends.
Help Desk of the UC Master Gardeners of Contra Costa County (SMH)
Vole damage to root crown and lower bark of a tree. Credit: Jack Kelly Clark, UC IPM
Vole damage to turf showing burrows and runways. Credit: Terrell P. Salmon, UC IPM
Hardware cloth barrier. Credit: S. Hoyer
Because they cannot climb the metal sides, your plants can be safe from voles in beds like these. Credit: S. Hoyer
Another very effective option is to add an (at least 12-inch tall) metal flashing barrier to wooden raised beds. Credit: S. Hoyer
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